Technical Field
The present invention relates to a biological information detection device or the like.
Background Art
In recent years, a biological information detection device which is mounted on a user's arm or the like and is used has been widespread. Biological information detected by the biological information detection device may include, for example, pulse wave information such as a pulse rate. The biological information detection device in this case is a pulsimeter in a narrow sense, and performs measurement or the like of a pulse rate of the user on the basis of a signal from a pulse wave sensor included in the pulsimeter.
In a biological information detection device mounted on the arm or the like, whether or not the biological information detection device is in a mounted state or an unmounted state is important information. For example, a case is assumed in which a pulse wave sensor includes a light emitting portion (an LED or the like) and a light receiving portion (a photodiode or the like), and the light receiving portion detects reflected light which is obtained as a result of light from the light emitting portion being reflected at a living body, or transmitted light which is transmitted through the living body. In this case, light to be detected by the light receiving portion is the reflected light or the transmitted light. If the biological information detection device is in a mounted state, the reflected light or the transmitted light can be detected, but, in an unmounted state, a relative positional relationship between the pulse wave sensor and the living body is not fixed, and thus the reflected light or the transmitted light cannot be appropriately detected.
In addition, in the unmounted state, there is a high possibility that the light receiving portion may detect external light such as ambient light, and, in this case, the pulse wave sensor outputs a signal value having no relation to a user's pulse. If the signal value having no relation to the pulse is wrongly recognized as a pulse wave signal, a calculated pulse rate or the like does not reflect a user's pulse state, and thus this also exerts an adverse effect on a process (for example, an advice process regarding a health state of a target user) using the pulse rate or the like.
If a mounted state of the biological information detection device is input by a user every time, the mounted state can be detected with high accuracy. However, such an operation is cumbersome, and thus there is an increasing demand for automatically determining a mounted state of the biological information detection device from the viewpoint of convenience of use.
For example, PTL 1 discloses that an output voltage value of a pulse wave sensor differs in a mounted state and an unmounted state. Therefore, a mounted state or an unmounted state may be determined by comparing a voltage value of the pulse wave sensor with a predetermined threshold value.